Coiled barbed tape has long been known as a barrier. It is essentially a coil of steel wire that has razor blades attached every few feet. Each portion of the coil that forms a 360 degree circle is called a “loop” herein. For increased strength and improved ease of handling, the loops of barbed tape can be connected to each other at staggered points. The material having connected loops is referred to herein as concertina, to distinguish it from a coil of barbed tape in which the loops have not been connected, referred to herein as simply a coil.
Historically, concertina is made by loading a coil of barbed steel wire onto a frame that rotates about a central axis. Then a man grabs a first loop of the coil and manually pinches it to the previous loop of the coil while simultaneously using a pneumatic gun to wrap a metal strip around the coils to attach them together. The metal strip is known in the art as a clip. Then, the man rotates the frame a given amount and grabs the first loop of the coil and clips it to the subsequent loop of the coil. The process results in alternate loops being attached to each other. This clipping-and-rotating is repeated until the entire coil is attached at desired points along the entire length of the coil. Loops attached five times are known as “5-clip” concertina in the art; “3-clip,” “7-clip” and “9-clip” configurations are also known in the art.
The conventional manual method of making concertina is dangerous and slow. The barbs are literally as sharp as razor blades and therefore will easily slice through skin. The steel coil is under tension due to the helix configuration (like a Slinky®) and therefore difficult to handle. Further, even a short coil of barbed steel wire is very heavy.
Therefore, it is an object of this invention to provide a faster and easier method and apparatus for clipping coils of barbed tape together to form concertina. It is another object to provide such method and apparatus to automate the connection of the loops of the coil of barbed tape.